People worry waaaaayyyyy too much about GVWR from a realistic standpoint.
My family is/was in logging/ranching/construction and I have seen pickups "overloaded" on a constant basis and the vehicles easily lasting 100K miles with no major problems.
Just make sure it has proper tires (that should be your primary concern) and some airbags/timbrens if you are really gonna work it. Oh, and remember you are driving a pickup, not a sports car.
I wouldn't hesitate to throw a ton of weight (literally) in this pickup....